1. Field of the Invention
The present invention relates to an ink for ink-jet recording, an ink-jet recording method, and an ink-jet recording apparatus.
2. Description of the Related Art
An ink-jet recording method is a method in which printing is performed such that an ink is discharged in the form of droplets to be adhered on a recording medium such as a paper sheet. In such an ink-jet recording method, for example, the ink in which a pigment is dispersed in a water-soluble dispersant is used.
In recent years, however, from the viewpoints that an optical density (OD value) is high and that a printed matter having superior image quality can be obtained, investigation is made actively about the ink in which a self-dispersible pigment that requires no dispersant is used, instead of the ink in which the pigment is dispersed in the water-soluble dispersant. The OD value is required to be further improved.
As a method for improving the OD value, a method in which pigment concentration in the ink is made to be higher can be assumed. However, merely increasing the pigment concentration arises a problem such that the stability of the ink is decreased. In the present description, there is disclosed a technique that the optical density is improved while maintaining the stability of the ink in the ink-jet recording.